Biomedical subjects

W J Yoon

Publications and source records attributed to W J Yoon.

10 recordsLinked to original sources

PubMed2006

Efficacy of alphas1-casein hydrolysate on stress-related symptoms in women.

OBJECTIVE: To examine the effects of alpha (s1)-casein hydrolysate on females with stress-related symptoms. DESIGN: Double-blind, randomized, crossover, placebo-controlled trial. SETTING: The alpha (s1)-casein hydrolysate was manufactured by INGREDIA (Arras, France) and the placebo was manufactured by DIETAROMA (Bourg, France). Study was designed and performed at PROCLAIM (Rennes, France), and the statistical analyses were performed by D Desor (Nancy, France). SUBJECTS: A total of 63 female volunteers suffering from at least one disorder that may be related to stress such as anxiety, sleep problems and general fatigue. INTERVENTIONS: A total of 63 volunteers participated in a double-blind, randomized, crossover, placebo-controlled study. Subjects were randomly allocated to receive either tablets containing alpha (s1)-casein hydrolysate or placebo at the dose of 150 mg/day for 30 days. After a 3 weeks washout period, they were crossed over for a new 30-day period of tablets intake. The outcome measure was a questionnaire including 44 items of symptoms that may be related stress in which the severity of each sign was evaluated using a 10-degree scale. These measures were studied repeatedly at the day of 0, 15 and 30 after the start of each interventional period. RESULTS: The 30-day treatment by alpha (s1)-casein hydrolysate in females with stress-related symptoms reduced their symptoms, particularly in digestion (P<0.01), cardiovascular (P<0.05), intellectual (P<0.01), emotional (P<0.05) and social problems (P<0.05). CONCLUSION: This study showed that a 30-day ingestion of alpha (s1)-casein hydrolysate decreased the stress-related symptoms in females suggesting that this product may be used as an effective functional ingredient alleviating such symptoms. SPONSORSHIP: This study was partially supported by the INGREDIA of France and Neurobiology Research Program from the Korea Ministry of Science and Technology (2004-01757) of Korea.

Adolescent↗

PubMed2003

Blockade of ionotropic glutamate receptors produces neuronal apoptosis through the Bax-cytochrome C-caspase pathway: the causative role of Ca2+ deficiency.

Blockade of ionotropic glutamate receptors induces neuronal cell apoptosis. We investigated if mitochondria-mediated death signals would contribute to neuronal apoptosis following administration of glutamate antagonists. The administration of MK-801 and CNQX (MK-801/CNQX), the selective antagonists of N-methyl-d-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptors, produced widespread neuronal death in neonatal rat brain and cortical cell cultures. MK-801/CNQX-induced neuronal apoptosis was prevented by zVAD-fmk, a broad inhibitor of caspases, but insensitive to inhibitors of calpain or cathepsin D. Activation of caspase-3 was observed within 6-12 h and sustained over 36 h after exposure to MK-801/CNQX, which cleaved PHF-1 tau, the substrate for caspase-3. Activation of caspase-3 was blocked by high K+ and mimicked by BAPTA-AM, a selective Ca2+ chelator. Reducing extracellular Ca2+, but not Na+, activated caspase-3, suggesting an essential role of Ca2+ deficiency in MK-801/CNQX-induced activation of caspases. Cortical neurons treated with MK-801/CNQX triggered activation of caspase-9, release of cytochrome c from mitochondria, and translocation of Bax into mitochondria. The present study suggests that blockade of ionotropic glutamate receptors causes caspase-3-mediated neuronal apoptosis due to Ca2+ deficiency that is coupled to the sequential mitochondrial death pathway.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

PubMed2001

Proapoptotic effects of tau cleavage product generated by caspase-3.

Using an in vitro translation assay to screen a human brain cDNA library, we isolated the microtubule-associated protein Tau and determined it to be a caspase-3 substrate whose C-terminal cleavage occurred during neuronal apoptosis. DeltaTau, the 50-kDa cleavage product, was detected by Western blot in apoptotic cortical cells probed with anti-PHF-1 and anti-Tau-5 antibodies, but not anti-T-46 antibody which recognizes the C-terminus. Overexpression of DeltaTau in SK-N-BE2(C) cells significantly increased the incidence of cell death. Staurosporine-induced Tau cleavage was blocked by 20 microM z-Asp-Glu-Val-Asp-chloromethylketone, a caspase-3 inhibitor, and in vitro, Tau was selectively cleaved by caspase-3 or calpain, a calcium-activated protease, but not by caspases-1, -8, or -9. (D421E)-Tau, a mutant in which Asp421 was replaced with a Glu, was resistant to cleavage by caspase-3 and tended to suppress staurosporine-induced cell death more efficiently than did wild-type Tau in both transient and stable expression systems. Finally, the incidence of DeltaTau-induced cell death was augmented by expression of Abeta precursor protein (APP) or Swedish APP mutant. Taken together, these results suggest that the caspase-3 cleavage product of Tau may contribute to the progression of neuronal cell death in Alzheimer's disease.

Amyloid beta-Protein Precursor↗

PubMed2001

1,2-bis(2-Aminophenoxy)ethane-N,N,N',N'-tetraacetic acid induces caspase-mediated apoptosis and reactive oxygen species-mediated necrosis in cultured cortical neurons.

Sustained alteration in [Ca(2+)]i triggers neuronal death. We examined morphological and signaling events of Ca(2+)-deficiency-induced neuronal death. Cortical cell cultures exposed to 20 microM 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA-AM), an intracellular calcium chelator, underwent neuronal apoptosis within 12 h that was evident by shriveled cell bodies, aggregated and condensed nuclear chromatin, and disrupted nuclear membrane. Thereafter, surviving neurons revealed typical necrosis, accompanied by swelling of cell body and mitochondria, over 24 h. Both apoptosis and necrosis were prevented by inclusion of 1 microg/mL cycloheximide, a protein synthesis inhibitor. Treatment with BAPTA-AM induced translocation of Bax into mitochondria within 4 h and release of cytochrome c from mitochondria over 4-12 h. An active fragment of caspase-3, a downstream mediator of cytochrome c, was observed within 8 h and cleaved PHF-1-positive tau. Administration of zVAD-fmk, a broad inhibitor of caspases, or DEVD-amc, a selective inhibitor of caspase-3, selectively prevented the apoptosis component of BAPTA-AM neurotoxicity. In contrast, BAPTA-AM-induced necrosis was propagated through sequential production of superoxide, mitochondrial and cytoplasmic reactive oxygen species. Combined treatment with caspase inhibitors and antioxidants blocked BAPTA-AM neurotoxicity. The present study suggests that neurons deficient in [Ca(2+)]i undergo caspase-3-mediated apoptosis and reactive oxygen species (ROS)-mediated necrosis.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

PubMed2000

Synergetic activation of p38 mitogen-activated protein kinase and caspase-3-like proteases for execution of calyculin A-induced apoptosis but not N-methyl-d-aspartate-induced necrosis in mouse cortical neurons.

We examined the possibility that p38 mitogen-activated protein kinase and caspase-3 would be activated for execution of apoptosis and excitotoxicity, the two major types of neuronal death underlying hypoxicischemic and neurodegenerative diseases. Mouse cortical cell cultures underwent widespread neuronal apoptosis 24 h following exposure to 10-30 nM calyculin A, a selective inhibitor of Ser/Thr phosphatase I and IIA. Activity of p38 was increased 2-4 h following exposure to 30 nM calyculin A. Addition of 3-10 microM PD169316, a selective p38 inhibitor, partially attenuated calyculin A neurotoxicity. Activity of caspase-3-like proteases was increased in cortical cell cultures exposed to 30 nM calyculin A for 8-16 h as shown by cleavage of DEVD-p-nitroanilide and phosphorylated tau. Proteolysis of tau was completely blocked by addition of 100 microM N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (z-VAD-fmk), a broad-spectrum inhibitor of caspases, but incompletely by 10 microM PD169316. Calyculin A neurotoxicity was partially sensitive to 100 microM z-VAD-fmk. Cotreatment with 10 microM PD169316 and 100 microM z-VAD-fmk showed additive neuroprotection against calyculin A. Neither PD169316 nor z-VAD-fmk showed a beneficial effect against excitotoxic neuronal necrosis induced by exposure to 20 microM NMDA. Thus, caspase-3-like proteases and p38 likely contribute to calyculin A-induced neuronal apoptosis but not NMDA-induced neuronal necrosis.

Amino Acid Chloromethyl Ketones↗

PubMed1998

Molecular cloning of a novel GTP-binding protein induced in fish cells by rhabdovirus infection.

We have cloned and sequenced a cDNA encoding GTP-binding protein from a fish cell, CHSE-214. The clone was 1493 bp long and contained an open reading frame encoding 364 amino acids. It has the five sequence motifs G1-G5 that are conserved in all GTP-binding proteins. Its amino acid sequences are strikingly different from those of the well-characterized G-proteins. However, sequences closely related to this protein are found in various kinds of species including human, Arabidopsis, Drosophila and archaebacteria, suggesting a novel subfamily within the superfamily of the GTP-binding proteins. Northern analysis indicates that this gene is constitutively expressed at a low level in normal cells but is induced by fish rhabdovirus infection at about 24 h post infection and disappears thereafter. Based on these observations, we propose that this protein represents an evolutionarily conserved novel subfamily of GTP-binding proteins which may play an important role in fish rhabdovirus infection.

Amino Acid Sequence↗

PubMed1995

Analysis of mutations of neurofibromatosis type 1 gene and N-ras gene in acute myelogenous leukemia.

Neurofibromatosis type 1 (NF1) gene is a tumor suppressor gene, and the NF1 gene product, neurofibromin, can downregulate the N-ras gene. Because the N-ras gene is often mutated in acute myelogenous leukemia (AML), we wondered if the NF1 gene might be mutated in those AML samples not having N-ras mutations. We investigated the mutational status of the N-ras gene and the FLR exon of codons 1371-1423 of the open reading frame of the full-length NF1 cDNA, which has a strong homology with the mammalian ras GTPase-activating protein (GAP), especially for a stretch of three consecutive amino acids (F, L, R), by single-strand conformation polymorphism analysis and direct sequencing in samples from patients with AML. Of 48 AML patients, 10 (21%) had point (missense) mutations of the N-ras gene involving codons 12, 13 and 61. However, mutations in the FLR exon of the NF1 gene were not detected in any of the AML samples. We also examined the difference of clinical response to induction therapy between AML patients with and without N-ras mutation. A significantly lower rate of complete remission was noted in individuals with N-ras gene mutations. These results suggest that mutation of the NF1 gene, at least in the FLR exon, is very rare in AML and the NF1 gene probably is not a functional complement of the N-ras gene mutation. The presence of N-ras gene mutation may be associated with a lower clinical response to antileukemic therapy.

Adult↗

PubMed1985

Testicular neoplasms in Hispanic brothers.

Two hispanic brothers developed nonconcordant testicular malignancies in an interval of 11 months. They represent the 36th report of familial testicular neoplasia. The problems deriving from poor patient compliance are documented.

Adult↗

PubMed1984

Malignant feminizing Leydig cell tumor.

A patient with a feminizing malignant Leydig cell tumor is presented. Hormonal assays revealed increased production of prolactin, estradiol, and total estrogens. Eleven years after the onset of his disease he remains clinically well.

Aged↗

PubMedDate not supplied

Submuscular periareolar approach to augmentation mammoplasty in Korean women.

Augmentation mammoplasty can be approached by various methods according to the type of implant and implantation site depending on the status of the patient or surgeon's preference. The advantage for submuscular placement is based on problems associated with subglandular placement, especially capsular contracture and sensory changes in the nipple, and interference with the interpretation of mammograms is avoided. There are fewer complications such as hematoma, infection, and extrusion of the implant with submuscular dissection and relatively avascular, minimal sensory changes in the nipple compared with subglandular approach. The submuscular periareolar approach to augmentation mammoplasty was first described in the 1970s. This approach provides easy access to both the subglandular and subpectoral planes. It also provides a central point of access for creation of the implant pocket, which allows for easier and more accurate dissection in all diameters. The resultant periareolar scar is usually minimal with less injury to breast parenchyme and eventual biopsy or mastectomy incision to be performed through or around the areola. During the period of March 1999 to January 2000, 19 cases of who received submuscular periareolar augmentation mammoplasty under general anesthesia resulted in favorable scars with accurate access to pocket margin, easier dissection, and less bleeding compared with submuscular transaxillary augmentation mammoplasty. In our experience with the submuscular periareolar approach to breast augmentation it was highly versatile, safe, and less painful; postoperative hematoma incidence was greatly reduced and breast tissue injury was minimized.

Breast Implantation↗